Human skin is composed of three primary layers: the stratum corneum, the epidermis, and the dermis. The outer layer is the stratum corneum. Its primary function is to serve as a barrier to the external environment. Lipids are secreted to the surface of the stratum corneum, where they decrease the stratum corneum's water permeability. Sebum typically constitutes 95% of these lipids. Abramovits et al., Dermatologic Clinics, 18:4 (2000). In addition to maintaining the epidermal permeability barrier, sebum transports anti-oxidants to the surface of the skin and protects against microbial colonization.
Sebum is produced in the sebaceous glands. These glands are present over most of the surface of the body. The highest concentration of these glands occurs on the scalp, the forehead, and the face. Despite the important physiological role that sebum plays, many individuals experience excess sebum production, especially in the facial area. An increased rate of sebum excretion is termed seborrhoea.
Seborrhoeic dermatitis is also associated with seborrhea. The condition is characterized by the appearance of red, flaking, greasy areas of skin, most commonly on the scalp, nasolabial folds, ears, eyebrows and chest. In the clinical literature seborrhoeic dermatitis may be also referred to as “sebopsoriasis,” “seborrhoeic eczema,” “dandruff,” and “pityriasis capitis.” Yeast infections are a causative factor in seborrhoeic dermatitis. The yeast thrives on sebum and leaves high concentrations of unsaturated fatty acids on the skin, thereby irritating it.
Acne vulgaris is associated with clinical seborrhea and there is a direct relationship between the sebum excretion rate and the severity of acne vulgaris. Although sebum production increases during adolescence (particularly in boys, because of androgen stimulation), increased sebum alone does not cause acne. Bacteria, most importantly P. acnes, feed on sebum and as a result are present in increased numbers in persons who have acne. Much of the inflammation associated with acne arises from the action of enzymes produced by the bacteria.
Acne vulgaris is characterized by areas of skin with seborrhea (scaly red skin), comedones (blackheads and whiteheads), papules (pinheads), pustules (pimples), nodules (large papules), and in more severe cases, scarring. It mostly affects skin with the densest population of sebaceous follicles, such as the face, upper chest, and back.                There are four key pathogenic factors of acne:        Follicular hyperkeratinization        Propionibacterium acnes (P. acnes)        Inflammation        Excessive sebum production (seborrhea)        
Acne is still a very underserved market with treatment options that are only marginally effective. Only one product, oral Accutane® (isotretinoin) that reduces sebum production has been highly effective, but at the expense of a black box warning with significant side effects including teratogenicity that require extensive patient monitoring. Accutane® is indicated only for acne which is severe and recalcitrant to other treatment.
Topical therapy is often preferred over oral therapy because of the reduced risk for adverse systemic effects. The most common topical drugs for acne can be divided into the following categories:                Retinoids (i.e., tazarotene, tretinoin, adapalene)        Antibiotics (i.e., clindamycin)        Benzoyl peroxide (BPO)        Others (i.e., dapsone, azelaic acid)        
While many topical therapies are available, none of them address all four factors and most specialize in a few of these factors. Currently, no topical therapies in the market address excessive sebum production. Sebum is produced by the sebaceous gland, which is an appendage of the hair follicle, so it makes sense to target the sebaceous gland for more effective therapy. Since P. acnes depends on sebum to live, reduction of sebum is also thought to indirectly reduce P. acnes. 
Topical retinoids primarily act by normalizing infundibular hyperkeratinization and reducing inflammation, hence topical retinoids remain a mainstay for treatment of mild-to-moderate acne. The current topical retinoid formulations do not inhibit sebum production and their use is often limited by local tolerability (i.e., skin irritation).
There is a need in the art, therefore, for topical compositions capable of reducing sebum production and treating the conditions associated with it.